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Post by toddmaples on Nov 17, 2014 18:36:24 GMT -5
So, I have the 58.5mm piston and jug installed. Engine will run with stock carb, but its running REALLY lean. This is a sealed carb.
I have another carb the same size(24mm), which has no jets in it. Does anyone know the factory jet sizes, so I atleast have somewhere to start with the tuning on this engine?
Any advice/experiences from someone in a similar situation would be appreciated too.
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Post by geh3333 on Nov 17, 2014 19:16:05 GMT -5
I've heard of some having a 103 main all the way up to a 108. I would start at a 112 main and go from there . you may be able to go with a 115. Any higher and I'd up the carb . actually if I were u I'd just go ahead and get a 28mm or 30mm carb . but if u have to stay with the 24mm you'll be fine with the 112 or 115.
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Post by geh3333 on Nov 17, 2014 19:22:52 GMT -5
Sorry I didn't mention the pilot . it the same story here also I've heard some say 35 ,38 and even 42 for a stock 24mm carb. You usually don't need to mess with the pilot if using a 24mm carb , however a 35 seems a little small to me . and I'm basing this on the 58.5 setup with a 24mm carb .
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Post by toddmaples on Nov 18, 2014 6:52:03 GMT -5
Sorry I didn't mention the pilot . it the same story here also I've heard some say 35 ,38 and even 42 for a stock 24mm carb. You usually don't need to mess with the pilot if using a 24mm carb , however a 35 seems a little small to me . and I'm basing this on the 58.5 setup with a 24mm carb . Thx Geh3333, ordered a 38 pilot and 100-140# set overnighted... shipping was more than the parts, but can't afford to be down a week... |
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Post by geh3333 on Nov 18, 2014 7:03:59 GMT -5
Sorry I didn't mention the pilot . it the same story here also I've heard some say 35 ,38 and even 42 for a stock 24mm carb. You usually don't need to mess with the pilot if using a 24mm carb , however a 35 seems a little small to me . and I'm basing this on the 58.5 setup with a 24mm carb . Thx Geh3333, ordered a 38 pilot and 100-140# set overnighted... shipping was more than the parts, but can't afford to be down a week... No prob , keep us posted on what size jet worked best for you. Also remember its always best to run slightly rich. |
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Post by toddmaples on Nov 18, 2014 7:26:25 GMT -5
Thx Geh3333, ordered a 38 pilot and 100-140# set overnighted... shipping was more than the parts, but can't afford to be down a week... No prob , keep us posted on what size jet worked best for you. Also remember its always best to run slightly rich. Yeah this 24mm Carb was sold as a 139qmb "performance" Carb for scrappy dogs "100cc" kit... its basically a stock 150cc Carb. Which explains this Carb running rich on my 139qmb engine even with a maxed bore, head, and exhaust. I was drowning that poor engine. Lol |
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Post by toddmaples on Nov 20, 2014 19:06:23 GMT -5
Got some time this evening to try out a new jet. Put a 114 in there with a 38 pilot. Also put on my uni filter with a short extension and high flow muffler. The "chrome" header needs modification to fit this P-code engine.
Primed the carb and she fired right over, but is running way rich.
Tomorrow will be the next size down, a 110.
I must say, the muffler sounds good though.
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Post by geh3333 on Nov 21, 2014 21:41:10 GMT -5
Got some time this evening to try out a new jet. Put a 114 in there with a 38 pilot. Also put on my uni filter with a short extension and high flow muffler. The "chrome" header needs modification to fit this P-code engine. Primed the carb and she fired right over, but is running way rich. Tomorrow will be the next size down, a 110. I must say, the muffler sounds good though. Is your head stock ? |
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Post by geh3333 on Nov 21, 2014 21:44:19 GMT -5
If you ever decide to get a new carb I'd go with a 28 or 30mm . I love my 32mm but I probably could have achieved the same results with a 30mm .
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Post by toddmaples on Nov 22, 2014 6:56:09 GMT -5
Got some time this evening to try out a new jet. Put a 114 in there with a 38 pilot. Also put on my uni filter with a short extension and high flow muffler. The "chrome" header needs modification to fit this P-code engine. Primed the carb and she fired right over, but is running way rich. Tomorrow will be the next size down, a 110. I must say, the muffler sounds good though. Is your head stock ? Yes, stock p-code head. Its my understanding that these P heads have better flow over stock gy6 heads. My current setup is advanced timing cdi, 58.5mm bore, and high flow muffler. I can see burning occurring in the header even with a 110 main and 38 pilot. Going to do a valve job today and try out the 35-110 combo. Post results later. |
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Post by geh3333 on Nov 22, 2014 7:48:23 GMT -5
Yes, stock p-code head. Its my understanding that these P heads have better flow over stock gy6 heads. My current setup is advanced timing cdi, 58.5mm bore, and high flow muffler. I can see burning occurring in the header even with a 110 main and 38 pilot. Going to do a valve job today and try out the 35-110 combo. Post results later. Where is the P located on the model number? Your engine is pulling much more fuel from the jet and the carb can not match the air flow. Usually a 115 works just fine with the mods you have , although a high performance head would probably help . I have an ncy 58.5 racing head , this one says high performance head so I'm not sure if its the same as my racing head or not . enviromoto.ecrater.com/p/3807704/ncy-585mm-gy6-150-perfromance-head |
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Post by toddmaples on Nov 24, 2014 7:13:05 GMT -5
OK guys, new question.
Running lean at idle, popping and stuttering from cracked throttle to about1/3 the way through...I'd need a larger pilot if I'm more than 3.5 rotations out on my a/f screw right? Just trying to wrap my head around this Carb tuning thing...
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Post by geh3333 on Nov 25, 2014 0:00:04 GMT -5
OK guys, new question. Running lean at idle, popping and stuttering from cracked throttle to about1/3 the way through...I'd need a larger pilot if I'm more than 3.5 rotations out on my a/f screw right? Just trying to wrap my head around this Carb tuning thing... Did you notice if the header has a bigger diameter opening then the stock ? I've seem some that said high performance but turns out the chrome was the only difference . popping on excel could be a rich condition . something is not adding up here . I'm concerned your stock head is restricting airflow making the free flow exhaust and air filter inefficient. |
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Post by toddmaples on Nov 25, 2014 7:13:45 GMT -5
OK guys, new question. Running lean at idle, popping and stuttering from cracked throttle to about1/3 the way through...I'd need a larger pilot if I'm more than 3.5 rotations out on my a/f screw right? Just trying to wrap my head around this Carb tuning thing... Did you notice if the header has a bigger diameter opening then the stock ? I've seem some that said high performance but turns out the chrome was the only difference . popping on excel could be a rich condition . something is not adding up here . I'm concerned your stock head is restricting airflow making the free flow exhaust and air filter inefficient. Found a cracked intake boot, was leaning way out since I first tried to tune the Carb. New one ordered, will try to tune again after install. |
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Post by geh3333 on Nov 25, 2014 7:16:25 GMT -5
Did you notice if the header has a bigger diameter opening then the stock ? I've seem some that said high performance but turns out the chrome was the only difference . popping on excel could be a rich condition . something is not adding up here . I'm concerned your stock head is restricting airflow making the free flow exhaust and air filter inefficient. Found a cracked intake boot, was leaning way out since I first tried to tune the Carb. New one ordered, will try to tune again after install. Good job , hope that fixes her. |
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